Transferring parts or workpieces in an automatic assembly machine generally requires three motions: a vertical upward motion to lift the part out of a storage device such as a hopper or magazine, a horizontal motion to move the part to another location on the machine, and another vertical but downward motion to place the part into an assembly or another station on the machine that does subsequent operations on the part. There are two independent directions of motion, a vertical motion and a horizontal motion. These two motions necessitate a control device to control the two independent motions and to sequence them properly in an automated machine. The sequencing operation very often necessitates sensing devices during the transfer to insure one of the three motions has taken place and is completed before the subsequent motion is initiated. The device described herein uses only one motion to accomplish this transfer. The need for three motions is eliminated by using a single curved motion that approximates an upward, then horizontal, then downward motion. The motion is generated kinamaticly using a sliding device and a set of gears. The elimination of one of the two independent motions, vertical and horizontal, of the prior art machines reduces the time for making a transfer of a workpiece from a first location to a second location, thereby increasing the speed of operation. Moreover, since only one motion is needed there is a reduction in the computer controlled operations for the transfer. These combine to reduce the cost and complexity of the workpiece transfer operation. Furthermore, and very significantly, a single motion transfer eliminates all of the complexity of synchronizing the two independent motions, the horizontal and the vertical, of the prior art devices.
The present invention has been found to be particularly useful for high speed manufacture of integrated circuit electronic components. In particular, the apparatus of the present invention can be used to pick up a semiconductor chip from a storage location and to transfer it to a bondhead which is used to bond contact locations on the semiconductor chip to the plurality of beam leads for electrically connecting the semiconductor chip to an electronic packaging substrate.
It is an object of this invention to provide an apparatus for transferring a workpiece from a first location to a second location along a substantially smooth curved motion.
It is another object of this invention to provide an apparatus to vertically pickup, to horizontally transfer and to vertically deposit a workpiece using one motion.
It is another object of this invention to provide an apparatus to deposit a workpiece at a location with substantially no vertical speed at the deposit location.
It is another object of this invention, transfer a workpiece from a first location to a second location along a trochoid like curve.
It is another object of this invention to achieve the trochoid transfer motion by rolling a cylindrical shaped member along a surface, wherein there is a workpiece pickup arm projecting along a direction parallel to the cylindrical surface.